Seed Production in New Zealand Browntop

New Zealand Journal of Agriculture, Volume 95, Issue 1, 15 July 1957, Page 7

Seed Production in New Zealand Browntop

By

J. G. RICHARDS,

Instructor in Agriculture, Department of Agriculture, Oamaru

OF the grasses introduced into New Zealand browntop has become one of the most common, for in many regions it has replaced much of the lowland tussock, particularly in Canterbury, Otago, and Southland. Its aggressive nature has resulted in what were once pure tussock swards becoming pure browntop swards. However, like other • plants it is a weed when growing where it should not grow on first-class and second-class lands which are capable of maintaining ryegrass-white clover or cocksfoot-dogstail-, red clover swards—but its presence as a constituent in pastures on much third-class, unploughable land is looked on with much favour.

K/TANY plants are often referred to by several common names, . and were it not for the use of standard botanical names there would be much greater confusion in understanding which plant was being referred to. Members of the grass genus Agrostis are no exception to this multiplicity of names, for Sir Bruce Levy, in “The New Zealand Journal of Agriculture” for February 1924,. recorded that the following names were used' to ' describe one or all of the three chief species, in that genus: Redtop, browntop, Waipu browntop, florin, twitch, creeping bent, carpet bent, velvet bent, Agrostis alba, A. vulgaris, A. ' capillar is, A. canina, A. stolonifera, A. palustris, and A. tenuis. .This example is one of the most extreme, but fortunately most of these discrepancies have been cleared up, > and the chief terms now in use are redtop, browntop, and creeping bent, known botanically as Agrostis alba, A. tenuis, and A. stolonifera respectively. Of the . three species, browntop (A. tenuis) is the most important in New Zealand agriculture and is grown over a wide range of soils and climates. ■■ ■' - ‘ Description of Plant Browntop is a fine-leaved, rather erect grass, and where it has room to spread short rhizomes are produced. The ligule at the base of the leaf blade is very small and often there is no ligule, contrasting with the prominent

and characteristic ligules displayed by redtop and creeping bent. This characteristic identifies browntop from the other two species. The leaves of browntop are about Jin. wide at the bases and taper gradually to points. A perennial plant canable of producin'* seed for several sSsons, ls P maVSty Is rather seed being harvested from mid-March to May in Otago and Southland. The seed head is fine and the plant in flower has a rather attractive purple tinge which gives a flowering field a distinctive appearance. Though three distinct species of Agrostis are recognised botanically, in the field a fairly wide range of types can be observed, suggesting that some crossing between the original species has taken place. As a result some browntop areas contain more than one type of plant. Coarse types of browntop and types showing a larger ligule, but otherwise typical browntop, are occasionally observed. In addition, a fairly distinctive type of browntop grows in certain localities, particularly on the Canterbury Plains. This type, which has been named dryland browntop, is not as suitable as true browntop for use as either a pasture plant or a lawn grass. . , , Distribution in New Zealand The distribution of brownton in New Zealand is possibly the widest of all introduced grasses, for it grows under a wide range of conditions — the coast to the upland tussock area, from North Cape to Bluff, and on good, poor, and indifferent soils. In some areas it is the dominant species, in some a major species, and in. others just another grass. On the bulk of third-

class, steep, and unploughable lands it is a most valuable species because as well as providing valuable grazing, it helps to bind the soil, thus lessenmg the ever-present menace of erosion. On the unploughable bush-burn country of the North Island its inclusion in the seeds mixture for surface sowings is advisable so that when the. ryegrass, cocksfoot, and clovers begin to run out the browntop is there to take their places and thus, by its ability to form a tight compact sward, assistto check reversion to fern manuka, and piripiri or bidi-bidi a a se Jo a syn. A. sanguts- '' ' Apart from its use as a pasture species, it is famed as a lawn grass, usually being sown with chewings fescue. , , . . Seed-producing Districts The production of browntop seed in New Zealand is confined mainly to the South Island, Otago and Southland being the principal areas. In Otago ciutha County is the main seed-pro-ducing area and in Southland Wallace and Southland Counties produce most o f tbe ed. Counties in Canterbury j- be boundaries of which include the foothill country also produce some seed, but the acreage saved for seed in those parts is much less than farther south. The counties in Canterbury which produce browntop seed a £ e Levels, Ashburton, Geraldine, Mackenzie, and Waimate. In favourable seasons small acreages have been harvested in parts of Nelson, Marlborou §b, and Hawkes Bay. The chief seed-producing areas are those where generally soil moisture is adequate. The soils of these areas

are somewhat stiff and heavy, and these conditions, combined with adequate moisture, are the best for browntop. . „ . A d fft q Xnt WhX tant for the browntop plant. Where ’ soils are inclined to dry out yields of seed are usually poor Ample dunng spring and early SSta J 2JKSS P duction of high yields of seed, browntop seed now harvested comes from paddocks and blocks of grazing land into which the plant has come as a volunteer. Seed is no longer sown to establish a seed-producing stand, better, high-producing seed crops being obtained at less cost by allowing the plant to establish naturally. This volunteer establishment is quite rapid; within 2 years from a bare field a dense browntop cover will arise which . can be harvested in another 12 months. A method that has been adopted for the estabUshment of a stand is to sow turnips, feed them off, and allow the browntop I 0 come in - With good seasons such a field should produce high yields of seed or 3 or 4 successive years. However the bulk of the seed comes from ar ® as that have been sown to pasture which has run out and which are to ]? e ploughed up within 2 or 3 years om the time the browntop becomes the dominant grass. Browntop begins to show up after a bout 3 years n pastures which have ad insufficient lime and phosphate and poor drainage, or if poor types of grass and clovers have been sown, Under these conditions browntop may become dominant within 4 years, When the ryegrass and white clover

For many years strippers in various forms were the chief machines used for the harvesting of browntop seed, but they are now used mainly for the harvesting of relatively small areas or parts of fields where it is uneconomic' for header harvesters to work.

die out these swards will produce crops of browntop seed .for 4 or 5 years. The pasture is then usually put under the plough. The average life of a sown sward on the browntop country of South Otago is 7 to 8 years. . In contrast to the poorly treated rye-grass-white clover pastures, those which receive adequate lime and phosphate, are drained, and contain good, persistent strains of grasses and clovers will not tend to run to browntop until they are 6 to 7 years old. Browntop seed may be harvested from such swards at., this age, but the swards are more likely to be ploughed without seed being harvested. Time of Closing Seed Areas Yields of seed are highest from fields which have not been grazed (for example, on abandoned properties), and where stock are grazed on areas which will be saved for seed they are usually

taken out in October. Sometimes fields are closed as early as September. Closing later than October is likely to be detrimental to seed yield. Once the seed is set, about FebruaryMarch, stock are sometimes allowed on the area to graze the bottom, but that is not common. Time of Harvesting The maturing of browntop seed, like that of numerous other plants, is rather uneven, and sound judgment is necessary to select the correct stage for harvesting. Flowering is late, most of it occurring during February in Otago and Southland and in late January in Canterbury. Fields of flowering browntop are a pleasing sight, for the

opened florets and exposed stamens impart a delicate purple tinge to the area. . Seed begins to mature 14 to 21 days after the plants flower, and with the fall of the sap the area appears ashen white. At this stage seed can be rubbed out, and though the bulk of the area may not be ready, harvesting is begun as soon as the completely formed seed appears. As large areas are usually harvested, it is imperative that the harvest begin as soon as the seed is ready so that as the season progresses all seed set is harvested and the best yields are obtained. The risk of loss from winds and other causes would be too great if the start of the harvest were delayed until all the seed was ripe. In South Otago the harvest begins about the middle of March and continues for 6 to 8 weeks, depending on the crop; in some years it has continued well into June. Older stands are earlier maturing and lower yielding than are younger ones, and consequently they are usually harvested first. Frosts at flowering time and high winds after the seed is set will lessen the yield. Browntop requires damp conditions for it to thrive, and yields have been high in damp seasons. In the 1954-55 season rainfall from December to March in South Otago was 10.9 in. with 7.46 in. of it falling in December and January. That season some 2754 sacks of field-dressed seed were harvested from 9789 acres. In the following year rainfall from December 1955 to March 1956 was only 5.94 in. Of this 3.66 in. fell in December and January. Only 489 bags of fielddressed seed were obtained from just under 4000 acres. Adequate moisture, particularly during December and January, is therefore all-important for high yields of browntop seed. If the seed is ripe, no heating will occur unless seeds of catsear are in the sample, when the danger of heating is ever present. These seeds often make it necessary for browntop seed to be run through a drier. By careful adjustment of their headers some experienced harvesters are able to reduce the content of this weed seed to a minimum. These seeds can be dressed out at machine dressing, but seed of another weed, Juncus bufonius, is difficult to remove and is the most common impurity in machine-dressed lines. Seed for export requires to be of a very high standard of purity. All seed eligible for certification must reach a minimum purity of 97 per cent, before being sealed and tagged, but most lines reach a purity of 99 per cent. Harvesting Methods Implements which have been or are now used in harvesting browntop seed are the reaper and binder, mower, chain drum and beater strippers, and header harvester. Believed to have been first used in Southland in 1919, the reaper and binder is now out of favour. Great

difficulty was experienced with wet sheaves, for once they took up moisture, conditions for good threshing could seldom be obtained. The fine, dense sheaf was bad for holding moisture at the band. To overcome this dampness sheaves were collected on sledges, taken to a central area, and covered to await threshing with a wooden mill. That method proved too expensive for the relatively low yield obtainable. Seven binders operated in one field in 1929, and the material was stocked and then stacked. Because of sweating at the band difficulty was experienced in threshing. The mower has also gone out of favour, as more efficient means of harvesting are now available. Chain and Beater Strippers Excellent samples of seed can be obtained with chain and beater strippers, but whereas 10 to 15 years ago thousands of acres were harvested by this type of machine, they are now used on only a relatively small area. Strippers have been replaced largely by the header and are now operated only on small blocks of 10 to 15 acres or as a follow-up after the header. On small ridges where header operation is unsafe or uneconomic the stripper is useful. One advantage of the stripper is that harvesting can be started earlier in the day than with the header and continued later. Illustrated on page 11 is a machine made in Balclutha and operating on the chain drum principle. Built for a farmer who has had long experience of harvesting browntop seed, this machine is capable of bar-

vesting many hundreds of acres a year, and will strip in average going 6 to 8 acres an hour, travelling at from 5 to 7 miles an hour. With this and other strippers the seed harvested contains a considerable quantity of straw, and the material is bagged for screening on the farm or dressing on a modern header. Screens are usually of home construction, made from fine netting which will allow seed to pass through but retain, the straw. In the middle 1930 s as many as six strippers would operate in one field, with a set of screens set up in the field to screen out the rough material and bag the seed for dispatch to the machine-dressing plant. The ordinary stripper is a cheap and efficient machine for the harvesting of small acreages, but its efficiency cannot rival that of a header on larger areas. The stripper has almost gone out of manufacture with the growing popularity of the header. Header Harvesters The header harvester is rapid and efficient for harvesting browntop seed from large areas, and on its introduction to this type of work in the middle 1930 s it quickly found favour, and now most browntop seed is harvested by headers. Seed from the header is sufficiently free from roughage and straw to be sent directly to the machinedressing : plant. That these machines are efficient is shown by the example of one farmer who forwarded 86 sacks of field-dressed seed for dressing and obtained 84 similar sacks of machinedressed seed.

In April and May, when most of the harvesting is done, atmospheric conditions are often damp. Rarely can harvesting be started before 10.30 a.m., and about 3.30 p.m., when the crop again begins to take up moisture, harvesting stops for the day. With the relatively few hours each day when the seed is in condition to be harvested satisfactorily, speed is highly important, and it is here the header finds favour. As the machine is complex, all adjustments must be correct. Particular attention must be paid to the air blast, and for best results the knife, drum, and riddles should be kept full. Ideal conditions for harvesting seed are a bright, sunny day and a light breeze. If the breeze is too strong, irregularities in threshing will occur, especially when the machine is turning across or travelling against the wind. . Sound judgment is needed to . see that the air blast is adjusted correctly or too much seed will be lost. With the machine travelling at 4 to 6 miles an hour brushes on the reel are a distinct advantage to sweep the straw away from the knife and give an even feed to the drum. On average rolling country a harvest of 20 acres a day is considered a good coverage . for a 12ft. header, though under ideal conditions and on easy country : up to 25 acres a day may be harvested. Under such conditions and in a good crop two sacks of field-dressed seed an hour should be obtained. To be remunerative a crop should yield off the header at least seven sacks of well-filled and welldressed seed daily. Contract Harvesting : Most browntop seed is harvested under contract by owners of header harvesters. The contractor carries all costs of harvesting and dressing the seed, and the total proceeds are then divided between the grower and con- . tractor according to a pre-arranged agreement. Rarely is a contract signed. Proceeds are usually shared on a 50-50 basis, but if the crop is heavy, the contractor may receive only 40 per cent., and if it is light, he may receive 60 per cent. This basis appears to be satisfactory to the grower of the seed and the contract harvester. Usually after the contractor finishes • with the crop small isolated ridges remain on which the header has not been able to operate. These areas are frequently harvested by the farmer . with a horse-drawn stripper. Yields An average yield of browntop seed is very difficult to arrive at. Most paddocks are large, and usually only the better portion of the area is har-

Yields

vested. Yields of up to 1001 b. per acre have been recorded from small areas, but probably one-third of that yield may be considered as an average over the total area harvested. At present prices this return is less than can be expected from better utilisation of the areas through liming and topdressing. ■ < - Maintenance of Seed Areas As the great majority of the area on which browntop seed is harvested is capable of carrying better grasses and clovers, the general trend of farming is to reduce and finally eliminate browntop from pastures. Consequently only in special circumstances are efforts made to foster the browntop. Conditions which would favour the encouragement of browntop are present on relatively large farms where it is not possible for the farmer to plough up the amount of run-out pastures that he should each year. As these run-out swards provide little financial return from grazing, efforts are made to make them more productive by encouraging the browntop in the hope that a good seed crop can be taken from them. Removal of the roughage from these fields by fire in late winter and early spring invigorates the growth of browntop. The burn must be rapid and cool, for if it is too hot, too much bottom is burnt out, and with the coming of the hotter and drier weather the surface of the paddock will dry out. Drying out of the soil at this time of the year is detrimental to the growth of browntop, which demands moist conditions. After, a good burn in early spring seed can be harvested in the next autumn. Yields from this type of sward are not very high, but in the following year or two good yields should be obtained. As well as burning for regeneration the skim plough is sometimes used. The browntop sward is skim ploughed in winter, and by the following February there is a good, vigorous stand of browntop. This method is rarely used now. Such a renewed sward will produce good yields for 3 or 4 years. Uses of Browntop Seed The widest use to which browntop is put in . New Zealand is its inclusion in seeds mixtures for the sowing out of unploughable hill country. Such land reverts readily to secondary growth such as manuka and fern, and as these lands are difficult to topdress, it is imperative that the seeds mixture sown include a range of species that will cover all fertility levels. As a lawn grass, especially when sown with chewings fescue, browntop is unsurpassed, and a mixture of these two grasses is now standard for the sowing of croquet lawns, golf greens, and tennis courts, where a fine, even, hard-wearing surface is required.

It is usual to sow one part of browntop to two parts of chewings fescue at about loz. per square yard. Seed Certification A scheme of certification covering browntop seed was inaugurated in 1930-31. Its. purpose is to identify lines of seed of typical browntop, free from coarse types and from creeping bent and redtop. Dryland browntop is excluded from the certification scheme. Only one class of seed is recognised — Zealand Certified browntop. Any area of browntop of known type is eligible for certification. . Before final sealing and tagging machinedressed seed must reach a minimum purity standard of 97 per cent. Exports and Prices For many years the United States took •by far the greatest amount of browntop seed, and later the United Kingdom was the chief purchasing country. Australia is now by far the greatest annual importer of New Zealand seed. The bulk of seed shipped is certified. The price of browntop has been subject to great fluctuations during the past two decades, causing much speculation by farmer and merchant. In recent years the price has varied from 3s. to 4s. per pound. In the 1954-55 season up to ss. per pound was paid by merchants for machine-dressed Certified seed. In 1934 the price was Is. 6d. Undesirable on Good Land Browntop seed has been harvested in New Zealand for 40 years or more, and during this period many types of Agrostis species have been harvested as browntop. Only with the introduction of the Government certification scheme could genuine browntop free from other types be recognised. In some years browntop seed has given high financial returns, but most of the browntop seed-producing area is ploughable land which by liming, topdressing, and the use of good grass strains is capable of much higher production. High prices . for browntop seed during the past few years have tended to keep too much of this land under browntop. Browntop has a definite place in the farm economy of New Zealand, as it is a most valuable plant on third-class, unploughable land, but its presence on better-class lands, where its incidence is much too high, is undesirable, for such land is capable of much higher production than it now returns under browntop dominance.